Former Scottish leader Nicola Sturgeon was on Sunday arrested as part of an investigation into financial irregularities, according to police.
Her detenton marks the third arrest in the probe, which has sent shockwaves through Scotland’s political system, long dominated by the Scottish National Party (SNP).
“A 52-year-old woman has today… been arrested as a suspect in connection with the ongoing investigation into the funding and finances of the Scottish National Party,” Police Scotland said in a statement.
A spokesperson for Sturgeon said the former SNP leader voluntarily attended an interview with police.
She was in custody and was being questioned by detectives, added police.
Sturgeon’s husband Peter Murrell, the former chief executive of the SNP, was arrested in April as part of the probe.
At the time, police raided the Glasgow home shared by the couple, erecting a crime-scene tent in the front garden, and SNP headquarters in Edinburgh.
Murrell has long faced questions over the alleged diversion of GBP600,000 ($750,000) in SNP donations that were meant to support its drive for Scottish independence.
He also failed to declare a personal loan to the party of more than GBP100,000.
Party treasurer Colin Beattie was also arrested in April.
Sturgeon made her final appearance as First Minister in the Scottish Parliament in March.
After more than eight years at the helm, Sturgeon said in February that she lacked the “energy” to carry on and was stepping down.
But the police investigation into Murrell, whom she married in 2010, had been a cloud over her head.
Murrell resigned from his SNP leadership post in March after the party falsely denied to media that it had lost 30,000 members.
The disclosure came as the SNP held a bitter election to replace Sturgeon as party leader and Scotland’s first minister, eventually won by Humza Yousaf.
Yousaf denied that Sturgeon had quit knowing the police investigation was about to come perilously close to home.
“Nicola’s legacy stands on its own,” he said.
Following Murrell’s arrest, Yousaf said “clearly it’s not great, and I think the sooner we can get to a conclusion in this police investigation, the better.
“I’ve never been an office bearer in the party, I’ve not had a role in the party finances,” he added.
Yousaf also said Beattie’s arrest was “clearly a very serious matter indeed” but added that he had not been suspended from the party as “people are innocent until proven guilty”.
The affair has plunged the SNP into deep crisis and damaged its dream for an independent Scotland.
Recent surveys show only around 45 percent of Scots back their nation leaving the UK — the same minority recorded in a 2014 referendum, which London insists settled the matter for a generation.